“Books to the ceiling, Books to the sky, My pile of books is a mile high. How I love them! How I need them! I'll have a long beard by the time I read them”—Lobel, Arnold. Whiskers and Rhymes. William Morrow & Co, 1988.

On the first day of Christmas, my true love gave to me
A partridge in a pear tree.

Compliments of the season. In this twelve-part series of short blog posts, I will dissect and demystify NoSQL technology. The relational camp derides NoSQL technology because NoSQL technology does not play by the rules of the relational camp. Therefore the relational camp is ignoring the opportunity to incorporate the innovations of the NoSQL camp into mainstream database management systems. For its part, the NoSQL camp derides the relational model as unable to satisfy the performance, scalability, and availability needs of today. I claim that the NoSQL camp derides the relational model because it does not sufficiently understand it. I will go so far as to claim that the NoSQL camp does not fully understand its own innovations; it believes that they are incompatible with the relational model and it therefore does not see the opportunity to strengthen the relational model. A very strong assertion which I will defend as I go along.

NoSQL technology is a “disruptive innovation” in the sense used by Harvard professor Clayton M. Christensen. In The Innovator’s Dilemma: When New Technologies Cause Great Firms to Fail, Professor Christensen defines disruptive innovations and explains why it is dangerous to ignore them: “Generally, disruptive innovations were technologically straightforward, consisting of off-the-shelf components put together in a product architecture that was often simpler than prior approaches. They offered less of what customers in established markets wanted and so could rarely be initially employed there. They offered a different package of attributes valued only in emerging markets remote from, and unimportant to, the mainstream.”

Established players usually ignore disruptive innovations because they do not see them as a threat to their bottom lines. In fact, they are more than happy to abandon the low-margin segments of the market and their profitability actually increases when they do so. The disruptive technologies eventually take over most of the market.

An example of a disruptive innovation is the personal computer. The personal computer was initially targeted only at the home computing segment of the market. Established manufacturers of mainframe computers and minicomputers did not see PC technology as a threat to their bottom lines. Eventually, however, PC technology came to dominate the market and established computer manufacturers such as Digital Equipment Corporation, Prime, Wang, Nixdorf, Apollo, and Silicon Graphics went out of business.

So where lies the dilemma? Professor Christensen explains: “In every company, every day, every year, people are going into senior management, knocking on the door saying: ‘I got a new product for us.’ And some of those entail making better products that you can sell for higher prices to your best customers. A disruptive innovation generally has to cause you to go after new markets, people who aren’t your customers. And the product that you want to sell them is something that is just so much more affordable and simple that your current customers can’t buy it. And so the choice that you have to make is: Should we make better products that we can sell for better profits to our best customers. Or maybe we ought to make worse products that none of our customers would buy that would ruin our margins. What should we do? And that really is the dilemma.”

Exactly in the manner that Christensen described, the e-commerce pioneer Amazon.com created an in-house product called Dynamo in 2007 to meet the performance, scalability, and availability needs of its own e-commerce platform after it concluded that mainstream database management systems were not capable of satisfying those needs. The most notable aspect of Dynamo was the apparent break with the relational model; there was no mention of relations, relational algebra, or SQL.